/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dialer.callcomposer.camera.exif;

import com.android.dialer.common.LogUtil;
import java.io.IOException;
import java.io.InputStream;

/** This class reads the EXIF header of a JPEG file and stores it in {@link ExifData}. */
class ExifReader {

  private final ExifInterface mInterface;

  ExifReader(ExifInterface iRef) {
    mInterface = iRef;
  }

  /**
   * Parses the inputStream and and returns the EXIF data in an {@link ExifData}.
   *
   * @throws ExifInvalidFormatException
   * @throws java.io.IOException
   */
  protected ExifData read(InputStream inputStream) throws ExifInvalidFormatException, IOException {
    ExifParser parser = ExifParser.parse(inputStream, mInterface);
    ExifData exifData = new ExifData();
    ExifTag tag;

    int event = parser.next();
    while (event != ExifParser.EVENT_END) {
      switch (event) {
        case ExifParser.EVENT_START_OF_IFD:
          exifData.addIfdData(new IfdData(parser.getCurrentIfd()));
          break;
        case ExifParser.EVENT_NEW_TAG:
          tag = parser.getTag();
          if (!tag.hasValue()) {
            parser.registerForTagValue(tag);
          } else {
            exifData.getIfdData(tag.getIfd()).setTag(tag);
          }
          break;
        case ExifParser.EVENT_VALUE_OF_REGISTERED_TAG:
          tag = parser.getTag();
          if (tag.getDataType() == ExifTag.TYPE_UNDEFINED) {
            parser.readFullTagValue(tag);
          }
          exifData.getIfdData(tag.getIfd()).setTag(tag);
          break;
        case ExifParser.EVENT_COMPRESSED_IMAGE:
          byte[] buf = new byte[parser.getCompressedImageSize()];
          if (buf.length != parser.read(buf)) {
            LogUtil.i("ExifReader.read", "Failed to read the compressed thumbnail");
          }
          break;
        case ExifParser.EVENT_UNCOMPRESSED_STRIP:
          buf = new byte[parser.getStripSize()];
          if (buf.length != parser.read(buf)) {
            LogUtil.i("ExifReader.read", "Failed to read the strip bytes");
          }
          break;
      }
      event = parser.next();
    }
    return exifData;
  }
}
